... (19 98 + 4k) = 19 982k + k(6k +1) Theo gi thit SB = SC nờn: 19 98.2k + k(6k +1) 19 98(2k +1) + k(2k +1) 19 98 k 23 6k2 + k 19 98 + 2k2 + k 4k2 19 98 k + Nu k = 23 n = 92 Tp A = {19 98, 19 98 + 1, ... 19 98 + 1, 19 98 + 2, , 19 98 + 92} vi B = {19 98 + 1, 19 98 + 2, , 19 98 + 46, 19 98 + 59} C = {19 98, 19 98 + 47, , 19 98 + 58, 19 98 + 60, , 19 98 + 92} Thỡ SB = SC = 95046 + Nu k > 23 Ta cú: A = A1A2 Trong ... 2k +1 phn t thỡ C cú khụng quỏ 2k + phn t Ký hiu : SB l tng cỏc phn t ca B thỡ: SB 19 98 + (19 98 + 1) + + ( 19 98 + 2k) = 19 98(2k +1) + k(2k +1) SC l tng cỏc phn t ca C thỡ: SC (19 98+ 2k +1) + (19 98+2k+2)...